Description: A test protocol and the performance criteria to determine the flame propagation tendency of flame-retardant coated cables in a vertical cable tray are covered. This standard applies to single and multiconductor cables. The test consist of exposing coated and uncoated cable samples to a theoretical 20 kW (70 000 Btu/hr) flame ignition source for a 20 min duration. The test facility, test sample requirements, test procedure, and evaluation of results are covered.